Tucked away in a quiet corner of a clamorous steak house in midtown Manhattan, at a safe remove from the pin-striped after-work crowd, Taylor Swift hunches over a notepad and contemplates her future. At the top of the page are four letters, M-A-S-H, denoting four categories of real estate: mansion, apartment, shack, and house.

Pretty much everyone under 35, especially the slumber party set, knows the game—everyone except Swift, who, although still technically a teen (turning 20 three days after we meet) and perhaps the most effective apostle of adolescence since Frankie Avalon, is not exactly representative of the species. "I think I've definitely played it before," she says. "It's been awhile, though."

In person, Swift's beauty is almost otherworldly. Tall and whiplike in a red cashmere sweater from Topshop, black Citizens of Humanity jeans, and Rag & Bone flats, all of it topped off with that cascade of corkscrew curls, she appears almost suffused with light, like a stage performer pursued by a follow spot. Her manner is girlish, but she's also extraordinarily self-possessed. She speaks in well-constructed sentences, pausing first to formulate her thoughts and unfailingly weaving the question she's been asked into her response the way media coaches recommend. And she's generous with hugs, which she tends to deliver sideways like a tall person (she's 5'11") who poses for a lot of photos. Al Wilson, her drummer and bandleader, met her three years ago and remains awestruck. "She just glows," he says, shaking his head like someone trying to describe a UFO. "She has an electricity that's just profound, man. She's wired so well it's unbelievable." (According to her best friend from back home in Tennessee, Abigail Anderson, Swift does have one teensy fault—an annoying tendency to clear her throat a lot— though to be fair, nobody else seems to have noticed.)

Returning to our attempt at junior varsity fortune-telling, the singer-songwriter is asked to name three cities she'd like to live in and fires off Nashville, New York, and Los Angeles. But when it comes to citing one she'd hate, Swift hesitates. The last thing she wants to do is snub some random municipality in a national magazine. She settles on the perfect answer: "Kablamphnar," which doesn't actually exist. I jot it all down, along with four numbers representing how many children she might eventually have.

Now for the tough part: Three guys you think are hot?

"Like, how do you mean?" she asks, scrunching up her face. She knows how I mean. "Um, well...Taylor Lautner," she says finally, a certain nervy resolve in her voice. The 18-year-old Lautner, the other half of what the tabloids dubbed "Taylor Squared," is the impish, abdominally gifted New Moon hunk who has played her beau onscreen (in the romantic comedy Valentine's Day) and off. She joked about the relationship in a charming Saturday Night Live monologue—her appearance, as both host and musical guest, was SNL's best-rated episode last fall, until, that is, Lautner hosted the show and reciprocated with a Taylor shout-out of his own. During our interview, she declines to chat about him at all, and wisely so: A few weeks later she cuts him loose, and a member of her camp makes sure Us Weekly has the proper spin.

Back to the game: Swift name-checks John Mayer and Carter Jenkins, another Valentine's Day costar, as her remaining hotties. I don't even bother to solicit a response to the last question: a guy she can't stand. I just write Kanye West.

"Oh my God, no you didn't!" she says, her almond-shaped eyes glinting a bit. "You're so scandalous. Do we have to?"

Relax, it's just a game, I tell her.

"Mmm, right," she says skeptically.

You can't blame Swift for being cautious; the girl's got a lot to lose. Her second album, Fearless, was 2009's best-selling in any genre, sticking to its No. 1 perch on Billboard's Top 200 for 11 weeks, longer than any album in a decade. Her first record is still among the top 100 three years after its release. Then there are the awards, including her 2010 Grammy wins—Best Album of the Year plus three more—last year's infamous Moonman for Best Female Video, and other shiny trinkets too numerous to mention. Though she's been embraced by the country greats, last year becoming the youngest recipient ever to be named Entertainer of the Year by the Country Music Association, many tracks on Fearless could be characterized as soft rock or pop. Nonetheless, "she's not going to be chasing pop music," insists Scott Borchetta, who signed Swift to a deal at his then-fledgling label, Big Machine Records, in 2005. "Pop music is chasing her."

The day after our dinner, Swift headlines the Z100 Jingle Ball, an annual concert at Madison Square Garden featuring a bevy of tween-friendly acts. It's late, and some fans are looking blearyeyed, out well past their bedtimes. Justin Bieber, the mop-topped hormonal heartthrob, has just delivered a rousing set, appearing in a leg cast (defying doctors' orders—or so he claims, to a chorus of "Awww..."), and it seems a tough act to follow. But then Swift appears, skipping across the stage in black knee-high boots, belting out "You Belong With Me," and Bieber is forgotten. Within seconds, the only thing shinier than Swift's spangled Jenny Packham dress is the thousands of glinting braces in the audience as her fans, some weeping, sing along to every word. After the song, Swift stands there for a generous while, smiling radiantly, her slender arms outstretched, just sort of marinating in it. A minute or so goes by and, just when our palms are beginning to sting, she gooses the applause with the merest side-flick of her electric blue eyes and stands there some more.

As talented a performer as she is, it's Swift's genius as a songwriter that's made her a star. Tales of unrequited crushes and teenage yearning, her pastel-color country-pop lullabies are, for the most part, stripped of grown-up temptations. Cozy, enveloping, and altogether irresistible, they're a perfect balm for a time when we seem to have run out the string on cynicism. Not merely innocent, they reaffirm the whole idea of innocence, transforming youthful naïveté from a fleeting embarrassment into an exalted Paradise Lost, and scattering bread crumbs you can follow all the way home, if you're willing. Approach a song such as "Love Story" or "Fifteen" with an open heart—playing it loud, over headphones, say, while running through the park at dawn—and the impact is so redemptive and affecting and true, you might be moved to wonder why you ever grew up at all.

Not for nothing has Swift been tagged the "anti-Britney." Whereas that other precocious blond songstress insisted she was "not that innocent," and then went on to prove it every way she could, Swift is a veritable Girl Scout. "Taylor's the perfect person for this media moment," Borchetta notes. "She really is the girl next door. She hasn't been drunk at a party, hasn't been in any crazy photographs. In this moment of total madness in the culture, Taylor's fans know they can count on her." Whatever experiences she's forsworn, Swift is somehow more composed and sophisticated than people many years her senior. Adds Borchetta: "I think parents just go, Oh, thank God my kids love Taylor Swift."

The singer—a committed teetotaler who likes to joke about her cookie-baking habit and is about to come out with her own line of greeting cards (there will be kittens, she promises, and glitter)— takes her role seriously. One of her biggest fears involves "me making a bunch of bad decisions and embarking on a painful, slow, devastating tailspin," says Swift, who discovered VH1's Behind the Music and E! True Hollywood Story as a child and remains a diligent student of the genre.

Asked to name the biggest mistake she's ever made, the only thing she can come up with is forgetting to scribble any diary entries during her week of SNL rehearsals. Still, she insists, "I've had countless opportunities to do some really bad things." Let's say she chose to hang out with the wrong people, Swift explains. They might influence her to make a bad decision, which would then hit the tabloids. "And then people start combing through everything that I do trying to find the next mistake and misperception," she goes on, clutching her sweater sleeves with her long fingers and pressing her fists together under her chin, "which leads to more scrutiny. Like, if I go to a bar, even if I'm not drinking, who's to say that a source isn't going to say that I was doing something I shouldn't have been doing? So it's not only about your own moral compass, but the moral compasses of other people that you don't know." She pauses, noticing my dumbfounded expression. "You're thinking, `This is a giant boatload of fear.' " (I am, especially for someone whose record is called Fearless.) "But as you can see," she adds, "I overthink everything. I overanalyze everything."

Fortunately, that analysis tends to demonstrate a Vulcan-like shrewdness. "Taylor's a very rational person," her mother, Andrea, tells me. "I was definitely crazier than she is. I know I had my first drink before I was 18. But it's not like she's really tempted. Her mind doesn't go there."

This spring, Swift will have more treacherous temptations to contend with when she moves out of her parents' house and into her own place, a three-bedroom condominium in a Nashville highrise. It's just a 15-minute drive away from home, but still. "Living by yourself, I mean, think about it—there's danger," Andrea says, conjuring a horrific scene out of a Final Destination sequel. "There's stepping in water and hitting the light switch. There's a bathtub overflowing. Just the whole safety issue...."

Perhaps most frightening of all, Swift might get stuck in her birdcage. In addition to a Juliet Capulet–style balcony overlooking the living room, the singer—who's doing her own interior decorating—has conjured up a chill-out lounge housed in a giant birdcage that will dominate the great room. The only way to reach it, she notes excitedly, is by crossing a pond via a strategically placed stepping stone and climbing a spiral staircase. "I just wanted it to be my fantasy world," she says.

Swift is a fan of fairy tales, and it's not hard to see why. Doted on by loving parents (father Scott is a stockbroker, Andrea a former marketing exec for mutual funds, who ditched her career to raise Taylor and her younger brother, Austin), she grew up on a farm in rural Pennsylvania. "Taylor's favorite thing to do was saddle up the pony for a trail ride or build a fort in the hay loft," Andrea says. She discovered country music at age six and began playing local events and karaoke contests while still in grade school. Then, after catching a documentary about Faith Hill, she begged her parents to take her on a trip to Nashville. "I just got it into my head that there was this magical place that I needed to go to because that was where dreams come true," Swift says. It's become country music legend now, the way a preadolescent Swift marched into one label after another along the famed Music Row (while Andrea waited in the car with Austin) presenting her homemade demo tapes.

Like every fairy tale, this one has a villain—a posse of them, actually. One day shortly after Taylor, then 12, played her biggest gig yet (singing the National Anthem at a 76ers game), she called her friends one by one, looking for someone to go with her to the local mall. No one could make it, so Taylor went with Mom. Andrea remembers what happened next "like yesterday," she says. "Taylor and I walked into a store, and these six little girls who had all claimed to be `really busy' were all there together.

"As a parent, there's no greater pain than watching your child being rejected by her peers," Andrea says. "But it made me realize, if she was ready to sacrifice being accepted and having friends for the lonely experience of writing songs in her bedroom and singing on weekends, it must mean a lot to her." A year later, the Swifts were bound for the Nashville exurb of Hendersonville, and at 14, Taylor had inked a deal as a staff songwriter at Sony/ATV publishing.

Swift later wrote a song about that trip to the mall, and I defy any parent to listen to "The Best Day" without reaching for a Kleenex (the way Andrea does every night when Taylor plays it on tour). Which points up one of the great ironies about Swift's lyrical output: The girl doesn't so much employ romantic clichés as cherish them like a collection of plastic ponies; yet even her dreamiest love songs are actually tethered to her own life experience (names unchanged to punish the guilty). And despite having had just three boyfriends (including, most notably, Joe Jonas), Swift seems in no danger of running out of material. "I like to categorize the various levels of heartbreak," she says, explaining that it ranges from level one, a simple letdown, to level ten, total heartbreak. "I've only had that happen once," she says. "A letdown is worth a few songs. A heartbreak is worth a few albums."

Pretty much everyone who knows Swift says the same thing: What you see is what you get. They mean it in a good way: She's not hiding anything. It's all out there, on her sleeve, in her songs, her videos, status updates, Twitter feed. (Sample Tweet: "Just wrapped up a cereal party with my mom and dad at the kitchen table. What a night." Which manages to be at once homey, self-deprecating, and perfectly on-brand, with 53 characters to spare.) Her YouTube channel includes footage of her getting fitted for a retainer.

Orthodontia aside, though, Swift is no ingenue. Whereas most recording artists have managers who guide their careers—and take 20 percent off the top—Taylor makes all the major strategic decisions herself. "We were looking around for a manager for awhile, and we realized, Wait a minute—it's her," Andrea says. "She knows exactly what she's doing and exactly who she is, and all we have to do is facilitate her ideas." Asked if she ever worries about how Swift might grapple with the extraordinary fame that's now coming her way, Mom says, "I used to wonder about that, but I got an answer early on. She never talked about fame or money. It was always, `What do I have to do today to get to tomorrow?' She's very evenkeeled. I feel confident that she has the temperament for it."

It's a sign of Swift's media savvy and sophistication as an artist that despite her considered approach to fame, she's not afraid to take risks, from her choice of cover songs (Eminem's "Lose Yourself," Rihanna's "Umbrella") and penchant for pranks (dressing up as Kiss's Ace Frehley during a show to punk Keith Urban) to her willingness to poke fun at her image, as she did in a sketch aired during the 2009 CMT Music Awards, rapping with T-Pain (sample rhyme: "I'm so gangster you can find me baking cookies at night / You out clubbing but I just made caramel delight").

That boldness, Borchetta says, paid big dividends during Swift's early days on "radio tour," driving from town to town, playing her songs acoustically for program directors around the country. "I told her, `They don't like to put new artists right on the air,' " he recalls. To which Swift replied, "Then that's the goal, isn't it?" Thereafter, every time a programmer complimented her music, she'd suggest an impromptu live broadcast. "I mean, checkmate," Borchetta marvels. "It was so adorable, you couldn't say no. It was deadly."

A few years on, the victims of Swift's lethal charm are piled up like cordwood, and she's just getting started. Next on the agenda: a valedictory second lap of the U.S. for the Fearless tour, releasing her greeting card line, reading the scripts that have been piling up since her SNL performance, and working on a new album. And when time allows, she'll hang out with Abigail in that giant birdcage.

And then? If M-A-S-H is any guide, she'll get married, move to an apartment in Los Angeles, and have 13 kids. Note to Carter Jenkins: Congrats, dude. Treat her well.